IN SPITE OF the recent observation of Welthy Honsinger Fisher, an active 99-year-old woman, that there are no books on how to live at 100, there is certainly a spate of books on how to plan for a successful and happy retirement.

Currently, about 15,000 people in America are 100 or over, and there is a 1500-person net gain every day in the population of those over 65. We can, therefore, expect even more manuals on how to age gracefully or at least how to cope with advancing years with some dignity and independence. However, if these books are to achieve their goals, they should be read long before retirement. Preventive health care, good nutrition and fiscal prudence over a lifetime (which are themes in most of the books under review) provided the best assurance of arriving at old age in good enough shape to enjoy it.

With the exception of The Rights Of Older Persons , there is not much comfort in any of these books for the very poor, very frail sole survivor. The purpose of this handbook (which is part of an ACLU series on citizens' rights) is to explain laws concerning Social Security, the Internal Revenue Service, ERISA (the pension reform act), age discrimination and others in such a way as to serve older people and their families, as well as social workers, nurses and lawyers who work with the elderly.

Areas covered, in a useful question and answer format, are "The Right to an Adequate Income," "The Right to Health Care," and "The Right to Freedom from Restraints on Life, Liberty and Property." Layman's language is used throughout to describe the history, intent and content of the laws as well as routes of appeal. While no such publication can cover all relevant laws, this one manages to be admirably comprehensive and comprehensible. Current as of September, 1978, it has 15 appendices which list sources for information and assistance from public agencies and private organizations. (Copies of The Rights Of Older Persons are available to the elderly and to organizations which serve them at $1.75 from the ACLU Literature Department, 22 e. 40th Street, New York City, 10016.)

If one had to choose among these books on the basis of general usefulness, Over 55 Is Not Illegal would be it. The format is conducive to easy reading, while the range of information -- community programs, newsletters, anticrime programs, volunteer and education opportunities, senior employment agencies, etc. -- is extensive. And if it doesn't answer all the questions it raises, it points to where answers can be found. The emphasis is on the reasonably well and reasonably well off. and the tone is activist.

The authors of Aging is a Family Affair are, respectively, director of social services and supervisor of social treatment at the Council for Jewish Elderly in Chicago. The book, which purports to be a guide not only for older people but for their children, is enlivened by anecdotes garnered over their years of experience, The number of people who reach retirement age with one or both parents still alive is increasing rapidly, creating new situations and anxieties for both generations, The chapter on "Death in the Family" is warm, compassionate and full of good sense. Readers should be warned, though: There are numerous errors of pagination in the table of contents.

Vital Maturity is a revision of To the Good Long Life , first published in 1974. Unfortunately, some of the references have not been updated. While Puner appears to acknowledge the loneliness, physical decline and fear of death experienced by many older people, the book is, in fact, addressed to the hope in all of us that we will be among the healthy old who will age slowly, have sufficient resources still to make choices in our later years, and die relatively quickly. There is a Norman Vincent Peale-ish quality to the tone which suggests that wishing will make it so.

The SAGE Program (Senior Actualization and Growth Explorations) can be best described as a movement which draws upon a number of developments in humanistic psychology and holistic health systems. Your Second Life is, in part, a chronicle of SAGE's own growth from its beginnings in program funded by the National Institute of Mental Health to the present. There are SAGE projects now in many parts of the country.

The book is also partly a guide for people who want to join or expand the movement. And in very significant part it can serve as a handbook for younger people who want to enjoy their youth and middle age as well as to control or prevent some of the stress and depression which characterize the lives of many older people. There are extensive descriptions of, and instructions for, exercises designed to enhance relaxation, self-possession and self-esteem.

Grace Weinstein's Life Plans is straightforwardly addressed to people approaching retirement age who expect to have a number of options when that day comes. After dispensing with the "myth" that retirement is a source of stress (most of us know people for whom that is no myth), a series of exhortations is put forward: "know thyself"; develop previously neglected interests and skills; decide rationally where to live (there are tables on comparative living costs in metropolitan and nonmetropolitan areas of the country based on 1977 Bureau of Labor Statistics figures); cement relationship with spouse and friends; plan for the unpredictable. Wish fulfillment figures prominently.

For people of any age who have not taken time to think about retirement or who are afraid to do so, any one of these books would serve as a useful and relatively painless first step.